Stuffed Shells

Ingredients

• 1 (12-ounce) package jumbo pasta shells
• 2 teaspoons olive oil
• 2 medium zucchini, halved lengthwise and cut into 1/4-inch-thick slices (3 cups)
• 1 (8-ounce) package mushrooms, cut into 1/4-inch-thick slices
• 2 garlic cloves, minced
• 1 (5-ounce) package fresh baby spinach
• 1/2 teaspoon kosher salt
• 1/4 cup chopped fresh basil
• 2 tablespoons dried parsley
• 1 1/2 teaspoons dried oregano
• 1/2 teaspoon crushed red pepper
• 1 (15-ounce) container part-skim ricotta cheese
• 6 ounces part-skim mozzarella cheese, shredded (about 1 1/2 cups), divided
• 1 (24.5-ounce) jar lower-sodium marinara sauce, divided
• Cooking spray
• 1/2 cup (2 ounces) grated fresh Parmesan cheese